PermaSEAL PRO 40P Green Roof Drainage & Storage Membrane 2m²

Intensive green roof drainage membrane - 40mm Studs

PermaSEAL PRO 40P is an intensive green roof membrane with impressive water storage capacity and drainage capabilities. The 40mm deep perforated cavities provide a water storage capacity of approx 15 l/m². This makes it ideal for green areas designed to do without irrigation for extended periods. It can support a wide variety of vegetation - plants, trees, grass and shrubs as well as being used in walkable and drivable deck paving drainage applications.

This extremely high performance drainage and water storage membrane layer is designed for intensive green roofs. It provides more drainage and water storage capacity than our PermaSEAL PRO 20P Green Roof Membrane. This makes it suitable for very large drainage lengths and/or very low roof slopes. It also has high compressive strength of approximately 200kN/ m² or 20 tonnes per m², ideal for laying beneath paving, slabs, drives with a gravel bedding.

As a green roof drainage membrane, PermaSEAL PRO 40P is perforated to allow water to pass through to the drainage space below. This prevents too much water accumulating and causing damage to the roots as well as preventing the sedum, grass or vegetation from becoming saturated. 

Uses of PermaSEAL PRO 40P Intensive Green Roof membranes

Our green roof drainage and storage membrane is suitable for intensive green roof systems in many horizontal applications. It is designed for the following:

• commercial and residential roofs including many storeys up
• inverted roofs
• balcony / terrace
• underground car parks
• ground level with basement living areas
• walkable and drivable decks
• hard-landscaping designs
• roof gardens

Typically PermaSEAL 40P Green Roof is used in conjunction with a primary waterproof coating above decks and flat roofs. As the membrane is perforated, it is also suitable for inverted warm roof applications.

Installing a PermaSEAL PRO Intensive Green Roof System

Once a primary waterproofing layer has been applied, you should then add a root barrier/slip layer. Once this is complete, you can lay the PermaSEAL PRO 40P intensive green roof drainage membrane slabs horizontally across the length of the roof with the cavity openings facing up. You should then cut the membrane to size where required. 

Joints should be acheived by butt jointing the membrane slabs next to each other, this will suffice for most applications but for added piece of mind some contractors may join each butt joint with PermaSEAL Overtape if you want additional root protection. PermaSEAL Overtape is a single sided waterproof butyl tape which can simply be stuck over the joint to act a root barrier and waterproof jointing strip.

A separate high quality geotextile layer is then installed over the laid surface. The planting substrate can now be applied directly to the intensive green roof membrane.    

Note: In walkable areas without vegetation, no geotextile is used and the cupsated cavities are filled.

For more information refer to our green roof design and construction guide.

Other products in the PermaSEAL intensive green roof system 

Root Barrier & Separation Layer – used as a slip layer/root barrier membrane between the primary waterproofing and 40P drainage and storage membrane.

PermaSEAL PRO MP 2C Flexible Waterproofing Compound – the primary waterproofing applied directly to the concrete roof deck or screed. Requires a scratch coat but no need for a primer.

PermaSEAL - Complete Solutions. Made Possible.

It is important that you select the correct intensive green roof membrane to suit your requirements. Our green roof drainage membranes function as part of a wider intensive green roof system. Please contact our technical department if you have any questions. Call us on 0117 982 3282.